Fixed API doc generation process.

Updated yaml2xml.py.
Updated ngx_http_api_module_head.xml.

Minor changes and switching to python3.
The code isn't compatible with python2 anymore.
1.1. Converting regex strings to raw stings
1.2. decode() the result to str
1.3. Adding workers to pretty_endpoint
1.4. Fixing time format
2.1. Remove closing </module> as it required by yaml/GNUmakefile
     erroneously introduced in https://hg.nginx.org/nginx.org/rev/8b8f94802f41

Author: eepifanova

xml/en/docs/http/ngx_http_api_module_head.xml

@@ -304,4 +304,3 @@ were added in <link id="api_version">version</link> 2.
 
 </section>
 
-</module>

yaml/yaml2xml.py

@@ -22,29 +22,29 @@ def node_description(node):
         return ""
 
     #
-    t = re.sub('\<code\>', r'<literal>', text)
-    t = re.sub('\</code\>', r'</literal>', t)
+    t = re.sub(r'\<code\>', r'<literal>', text)
+    t = re.sub(r'\</code\>', r'</literal>', t)
 
-    t = re.sub('\<i\>', r'<value>', t)
-    t = re.sub('\</i\>', r'</value>', t)
+    t = re.sub(r'\<i\>', r'<value>', t)
+    t = re.sub(r'\</i\>', r'</value>', t)
 
-    t = re.sub('\<a href=\"(.*?)\"\>(.*?)\</a\>', r'<link url="\1">\2</link>', t)
+    t = re.sub(r'\<a href=\"(.*?)\"\>(.*?)\</a\>', r'<link url="\1">\2</link>', t)
 
     # [desc](url)
-    t = re.sub('\[(.*)\]\((.*?)\)', r'<link url="\2">\1</link>', t)
+    t = re.sub(r'\[(.*)\]\((.*?)\)', r'<link url="\2">\1</link>', t)
 
     # ** foo ** is value
-    t = re.sub('[*?][*?](\w+)[*?][*?]', r'<value>\1</value>', t)
+    t = re.sub(r'[*?][*?](\w+)[*?][*?]', r'<value>\1</value>', t)
 
     # * foo * is literal
-    t = re.sub('[*?](\w+)[*?]', r'<literal>\1</literal>', t)
+    t = re.sub(r'[*?](\w+)[*?]', r'<literal>\1</literal>', t)
 
 
-    return t.encode('utf-8').rstrip()
+    return t.encode('utf-8').rstrip().decode()
 
 
 def pretty_endpoint(ep):
-    return ep.replace('/slabs/','slabs').replace('/resolvers/','resolvers').replace('/http/','HTTP ').replace('/stream/','stream ').replace('s/','s').replace('_',' ')
+    return ep.replace('/slabs/','slabs').replace('/resolvers/','resolvers').replace('/http/','HTTP ').replace('/stream/','stream ').replace('/workers/','workers').replace('s/','s').replace('_',' ')
 
 
 # human-readable html element id based on path
@@ -73,8 +73,8 @@ def multiple(str):
     return str + last
 
 def uncamelcase(name):
-    s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
-    return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()
+    s1 = re.sub(r'(.)([A-Z][a-z]+)', r'\1_\2', name)
+    return re.sub(r'([a-z0-9])([A-Z])', r'\1_\2', s1).lower()
 
 def make_defid(str):
     return 'def_' + uncamelcase(str)
@@ -395,7 +395,7 @@ def json_simple_type(obj):
 
     elif isinstance(obj,datetime.datetime):
         t = obj.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3]
-        z = obj.strftime("Z%Z")
+        z = obj.strftime("Z")
         return '"' + t + z + '"'
 
     else: